This article will help you creating a Subdomain under your cPanel account.
Procedure
Log into cPanel on the account to add the subdomain on.
Click “Domains” under the “Domains” section.
Click the “Create A New Domain” button.
Enter the subdomain name to add in the “Domain” text box.
Deselect the “Share document root (/home/username/public_html) with “domain.tld”.” option.
Enter the directory where you want the files for this subdomain to exist.
Click the “Submit” button.